An opposition activist was detained and beaten on Sunday after he tried to enter Moscow's landmark Christ the Saviour Cathedral to pray to deliver Russia from Vladimir Putin.

Several riot police officers forced Roman Dobrokhotov into a police car outside Russia's largest church, widely seen as a symbol of resurgent Orthodox Christianity after seven decades of atheist communist rule.

Another activist, Mariya Baronova, of the Resistance anti-Kremlin group, entered the cathedral but was cornered by a group of Orthodox priests and men who tried to escort her out.

A dozen activists from the militant Union of Orthodox Banner Bearers group lined up in front of the cathedral shouting obscenities at Dobrokhotov and Baronova. The group has previously dispersed gay rallies, protested against Madonna's shows in Russia and burned Harry Potter books.

Hours later, when Dobrokhotov was leaving the police station where he was held, seven men assaulted him, he said.

"They looked like soccer fans," he said. Opposition leaders have long claimed that pro-Kremlin youth movements hire football gangs to disperse anti-Kremlin rallies and beat government critics.

In February three members of the feminist punk rock group Pussy Riot held an anti-Putin prayer at the cathedral. They face up to seven years in jail, and their treatment has provoked a public outcry and contributed to growing criticism of the church.

Russia's Patriarch Kirill has described the punk performance as blasphemous and part of a broader attack on the church. The patriarch joined the Kremlin in calling anti-Putin protests a threat to Russian statehood.

Opposition protests drew tens of thousands to the streets of Moscow before the presidential election in March that gave Putin, currently serving as prime minister, a third presidential term. Putin's inauguration is scheduled for 7 May.